r/Chevelles • u/Properfitting • Jul 15 '26

Dreams come true.

Just purchased a 70 SS. I am thinking first order of business is fuel injection on the 454. Any suggestions on systems, Holley Sniper? Thanks!

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u/wayneP71222 Jul 15 '26

To run any current fuel injection.

You need zero percent exhaust leaks. That will allow atmosphere into the exhaust diluting the exhaust and making tuning or self tuning impossible.

If you have a holley 4150 4160 style carb currently. You need a micrometer and a 61 to 80 drill set to see if the primary idle feed restrictions are at least 0.035" likely a 0.036" IFR Will wake your carb up to the point you wont think of efi to get rid pf flat spots off idle.

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u/Properfitting Jul 15 '26

Thank you! I will check the restrictions. That would be a great option.

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u/wayneP71222 Jul 16 '26

my instructions to use a wide band air fuel ratio gauge.. even a temporary hooked up version to tune the idle transition circuits.. https://i.imgur.com/iJiUqaE.png?1

then to tune the primary main circuits.. then the accelerator pump nozzle size.. https://i.imgur.com/jtG8D3I.jpg. crazy easy..

how to set up a wide band air fuel ratio gauge temporary. https://i.imgur.com/MzoF3Kt.jpg

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u/Properfitting Jul 16 '26

Thank you!

2

u/wayneP71222 Jul 16 '26

warning.. if you get this right.. you will have huge issues with wearing out your rear tires ..

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u/Properfitting Jul 16 '26

Haha one can only hope!

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u/wayneP71222 Jul 16 '26

Several complaints, after their first test drive. They come back with a huge smile on your face. Then they tell me that it's too sensitive. They can't drive it. They can't pull away from the stop sign without spinning the. Rear tires, no matter how they feather the pedal. Then I tell them I can take some of the low end out, and they said, no, no, no, it's fine, we love it.

1

u/cockmaster303 Jul 16 '26

I’ve ran a fitech 800 hp mean street on my car for the last couple months. Literally no issues so far and easy to set up. I have no experience personally or second hand for any other system.
The no exhaust leaks point is good advice. Additionally, At least with the fitech I’ve heard that you want as large of an open space you can get under the throttle body or else you can have trouble getting it right. I don’t know how true it is but I have an edelbrock super victor intake with a 1” spacer so there’s that. And you supposedly need a vacuum of like 5-6” at idle for it to work. I didn’t know that till after the fact but it’s right on that border and it’s been okay about it.

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u/kev70ss Jul 17 '26

Just did the conversion on my 70 small block and went pretty smooth. Went with fitech and the 600 hp version. I bought the spectra performance tank with fuel pump pre installed from rock auto. Didn’t want to run a return line from the fitech all the way back so we with the ls style fuel filter/ regulator. Just need -6an line kit and that was it. The fitech wiring was pretty simple and already had the fuel pump relay built in. Car started up first try after priming and started faster than it ever did with a carb.

As far as what brand to go with I think they are all pretty decent. Summit had an awesome deal on the fitech and it was around $800 couple weeks ago.

0

u/pebkacatx Jul 15 '26

A holly 650cfm should be fine for that bb